A new mobile information environment has been gradually formed with the rapid development of the computer network technology in the world. In this environment, the mobile information service in the university library is able to meet the changing need of readers for the specific information online and need not visit libraries. The potential demand, opportunities and challenges of the mobile information service in the university library are analyzed respectively. At last, some advices are proposed to provide a better mobile information service in order to meet readers’ need for information in today's society.